Tooth psoitioners are devices which are adapted to surround the teeth of the wearer to support the teeth and adjacent arch forms and/or to direct the teeth and arch forms toward the assumption of preselected ideal positions. Tooth positioners are often generally U-shaped polymeric pieces having negative dental impressions on their upper and lower surfaces.
Such devices have been made in a number of ways. Nearly every positioner-forming method involves exposing a polymeric material (in some form) against toothwork models representing the upper and lower teeth. Typically, the methods involve the application of heat in some fashion and often the application of pressure as well.
During the last fifty years, a number of significant advances have been made in the field of orthodontic appliances, including advances in the manufacture of tooth positioners. A number of United States patents have been granted which disclose various devices and methods for production of orthodontic tooth positioners. Included among these are:
U.S. Pat. Nos. 2,531,222 (H.D. Kesling); PA1 2,775,036 (H.D. Kesling); PA1 3,316,640 (P.C. Kesling); PA1 3,407,500 (P.C. Kesling); PA1 3,429,045 (Anderson et al.); PA1 3,510,946 (P.C. Kesling); PA1 4,055,895 (Huge) PA1 4,073,061 (Bergersen); PA1 4,184,129 (Gordon); PA1 4,370,129 (Huge); PA1 4,419,992 (Chorbajian); PA1 4,448,735 (Huge); PA1 4,504,225 (Yoshii); PA1 4,505,673 (Yoshii).
Despite the advances in the art, it is recognized that there are significant practical problems inherent in existing positioner manufacturing methods. More specifically, the heating and forming steps of many prior methods are very slow, requiring a number of manipulative steps and often requiring equipment which is complex and expensive.
As a result, positioner manufacturing is typically a multi-step procedure, often involving steps at several sites and often resulting in a turn-around time which is medically disadvantageous.
There is a clear need for an improved positioner manufacturing method and apparatus overcoming such problems. More specifically, there is a need for an improved apparatus and method which will make is possible for local laboratories, which can meet the requirements of a limited group of nearby orthodontists, to manufacture tooth positioners without making large capital investments. There is a need for a tooth positioner manufacturing method and apparatus which will reduce the turn-around time and thus improve the practice of orthodontic dentistry.